The central objective of this investigation is the development and testing of explicit causal models of the long-term antecedents and consequences of depression in a community population. The specific aims include: to extend an integrative causal modal developed for a one year panel study to a four year panel study incorporating the constructs of depression, physical illness, alcohol use, stress, social support, coping and self-esteem; to assess the extent to which the impact of acute and chronic stress on depression is modified or buffered by coping styles, self-esteem, social support and alcohol use; to assess the extent to which patterns of informal help-seeking and social support affect the impact of depression on general medical and mental health care utilization; and to assess the impact of prior mental health care utilization on the subsequent natural history of depression. The data base consists of a five wave panel study of a representative sample of Los Angeles County adults interviewed four times (at four month intervals) over one year (1979-1980) and once four years later (1983). Thus, long-term causal influences will be assessed for a maximum time span of four years and a minimum time span of three years. Of the 1,003 participants in the initial interview, 820 remained in the study at the end of one year, and 676 participated in the final interview at the end of four years. Attrition throughout the study was mainly due to an inability to locate or contact the respondent; attrition effects on the data have been shown to be minimal for the one year panel. The main method of analysis will be latent variable causal models or Linear Strutural Relationship (LISREL) models. The primary advantage of this method is that the use of multiple measures for each construct in the model permits the separation of measurement error from true scores so that causal influences are assessed among error-free latent variables or factors. In addition to the standard methods which have already been used in the analysis of the one year panel, recently developed asymptotically distribution-free methods will also be used. Log-linear and linear probability models will be used to assess moderator effects for stress-buffering models of social support, alcohol use, coping and self-esteem. In addition, standard statistical techniques such as multiple regression and analysis of covariance will be used where appropriate.